Resistance unit



March 3l, 1936. J, MUCHER 2,036,071

' RESISTANCE UNIT Filed oct. 4, 1934 2 Sheets-sheet l fq 2 5 T274.

WITNESSESI Y INVENTOR ATTORNEYS March 31, 1936 J. J. MUCHER RESISTANCE UNIT Filed Oct. 4, 1934 2 Sheets-Sheei. 2

INVENToR y Jo/m f MM5/IEW WITNESSES i J@ o?? BY m47 @WV ATTORNEYS has for an object' to .used

Figure 2, but showing Patented M. 31, 1936 UNITED STATES PATENT OFFICE Z Claims.

This invention relates to resistance units, and

provide an improved construction which is an improvement over Patents No. 1,976,624, issued October 9, 1934, and No. 1,982,475, issued November 27, 1934, and also over my prior application for patent, Serial No. 739,316.

A further object of the presentinvention is to provide a resistance unit particularly adapted to be used in connection with a pilot light in a radio set, the structure being such that a certain part of the unit varies its resistance as it heats up.

Another object of the invention is to provide a resistance unit wherein there is providedva single metal casing with proper insulation, and a standard resistance unit associated with a temperature coeicient resistance unit,'the association being such that the heat from the standard resistance will quickly heat the temperature coeicient resistance.

In the accompanying drawings- Figure` l is a perspective view disclosing an embodiment of the invention, the same being shown the position in which the unit is usually Figure 2 is a vertical sectional view through Figure 1, the same being illustrated as being secured to part of the chassis of a radio or other support:

Figure 3 is a perspective view of the temperature coeilicient resistance shown in Figure 2;

Figure 4 is a plan view of the standard resistance shown in Figure 2;

Figure 5 is a transverse sectional view through Figure 2fapproximately on the line 5 5;

Figure 6 is a View similar to the upper part of a modified structure ci temperature coefilcient resistance wherein there are provided three terminals instead of two;

Figure 7 is a diagram showing how the resistance unit shown in Figure 1 is inserted into the circuit of the radio;

Figure 8 is a view similar to Figure 'l showing an additional tap or terminal to take care of two pilot lamps; l

Figure 9 is a bottom plan view'of a slightly modied resistance unit before the partshave been completely assembled, the same illustrating the position of the temperature-coefficient resistance;

- Figure 10 is a plan view of a strip of insulation adapted to tel placed on top of the resistance shown in Fig. 9;

Figure 11 is a plan view of a Standard resistance element adapted to be placed on top of the insulation shown in Figure 10 when assembled;

Figure 12 is a longitudinal vertical sectional view through the completed device, illustrating all parts in proper position; 5 Figure 13 is a transverse sectional view through Figure 12 on the line I3-I3;

Figure 14 shows a filament circuit in which a gpilot resistance or temperature coeilcient resistance is used, with a voltage dropping resistor, 10 but with the parts positioned with no common connection.

The resistance unit embodying the invention and as shown in Figs. 1 and 2 may be used in a number of situations and places, but is particu- 15 larly adapted for use in connection with transformerless radio receivers having pilot lights. Heretofore various means have been provided whereby a pilot light may be presented either to indicate that the current is on or to provide proper illumination. In the present invention a unit has been provided .which provides ay proper drop in voltage for the various radio tubes of the radio set, in which proper care is taken of the pilot light to cause the same to light up quickly and be functioning fully by the time the radio set functions, so that a person may readily tune the instrument. In utilizing the unit, which will be hereinafter fully described, the same may be arranged in various ways in the circuit of the radio receiving set as, for instance, by the arrangement shown in Figs. 7, 8 and 14. In all these arrangements the pilot light is protected and supplied at first with a comparatively low voltage' which rapidly increases to maximum, so 35 that the full illumination of the pilot lamp may be quickly secured.

Referring particularly to Figs. 1 to 4, inclusive, it will be observed that there is provided a metal casing I foreach unit, said casing being made 40 preferably of one piece of metal and formed in any desired shape. In forming the casing I openings 2; 3 and 4 are provided for the various terminals 5, 6 and 1 at the upper end of the unit. Arranged as shown in Fig. 1 there is provided a turned over 45 ilange 8 to close the end part of casing I, and at the opposite end there is a turned over portion 9 which is bent to present a supporting bracket I0, said bracket having an aperture whereby a bolt or other securing member I I may secure the same to a desired support I2, which may be the chassis of a radio receiving set. Arranged within casing I is a lining I3 of asbestos or other insulating material which is clamped firmly in place as shown in Fig. 5. This insulating lining is provoltage.

the terminals 5 and 6 extend, said terminals also extending through the openings 2 and 3. The insulating material holds the terminals centrally of the openings 2 and 3 and out of contact with the casing I. nected with the temperature coecient resistance i6, as shown in Fig. 3, the inner end of the terminals being each provided with a base II and turned over flanges i8 and I9 which grip-the resistance i6 and press against the wires thereof so as to provide a mechanical construction which is desirable, and also a good electrical connection. This resistance may be made out of suitable temperature coeicient wire as, for instance, pure nickel or iron, and when cold presents a certain resistance, but as it becomes heated the resistance increases, thus permitting more of the available current to flow through the pilot lamp which increases itsillum'ination. This action is very desirable as it takes care of the pilot light 28 when thev parts are arranged as shown in Fig. '7.

. As illustrated in Fig. 2 the entire structure shown in Fig. 3 is placed in position with the terminals 5 and 6 extending through the insulation and the terminal bases pressing tightly against 'the insulation. A narrow strip 2l of suitable insulating material as, for instance, mica, is then mounted in position so that one end, will abut against the edges of the flanges I8 and I9 but will not cover these flanges. This strip of mica extends over the anges I8 and I8 of ter mnal S and completely covers the same.- The end opposite that of the adjacentterminal 5 is placed below the base 22 of terminal 1, said base merely being a right angled ange extending from the inner end of terminal 1. By placing the insulating strip 2l in this manner terminals 5`and 'I have their bases exposed, so that when the standard resistance 23 is placed in position as shown in Fig. 2, a number of turns of the wire of resistance 23 will press against the flanges I8 and I9, and at the opposite end a number of turns of the wire will press against the base 22. After the resistance member 23 has been placed in position, the asbestos covering is then folded over and the metal casing I pressed tightly into the position shown in Fig. 5, whereby all the parts will be clamped together and held together, the action of the asbestos and the metal casing presenting a slightly clamping action at all times so that there will always be a good contact between the various parts. In addition the resistance member 23 is placed veryclose to the resistance I6, and the use of mica is desirable as it permits the heat to be quickly passed from resistance member 23 to resistance I 6 to heat resistance I6 quickly and, in

fact, almost simultaneously with the heating of Aresistance member 23. When current is turned on it will pass from wire 24 (Fig. 7) to resistance member 23, and then to wire 25. From wire 25 some of the current will pass through resistance n I 6 to wire 26, and the remaining part of the current will pass from wire 25 to the pilot light 20. If the pilot light 20 is a 6-volt lamp when the current is rst turned on, less than six volts will be applied across the lamp and a greater percentage will pass .through resistance I6, but as resistance I6 is heated by the heat from resistance member 23, more and more current will pass to pilot lamp 28 until this lamp has secured its full The current passing inv the circuit just mentioned will then pass through the various radio tubes 21 of the radio ,receiving set and out through the return wire 28.. For instance, as an 'I'he terminals 5 and 6 are convided with apertures I4 and it through which example, if the radio tubes 2.1 each take six volts. it will require thirty volts to'take care of all these radio tubes, and consequently, if the supply of current passing along wire 2d is 110 volts the resistors must take care of the diiference between thirty and one hundred and ten volts as far as the radio tubes 21 are concerned. The parts are so proportioned that the drop in voltage gives the desired voltage to the pilot light 28 and at the same time the desired voltage to the radio tubes 27. If the pilot light 28 should at any time burn out the radio tubes 2I will still be supplied with current passing through resistance i8.

Instead of having a resistance as shown in Fig. 3, the same idea may be used but a third terminal provided. As shown in Fig. 6 there is provided a temperature coeicient resistance 29 which has terminals 5 and 6 in a similar manner to that shown in Fig. 3 and, in addition, an intermediate terminal 38 which is of the same structure as the other terminals but presenting an extra tap.

v Aside from the terminal 30 the construction is identical to that shown in Figs. 2 and 3, and therefore will need no additional description. However, the structure shown in Fig. 6 permits two pilot lights to be used, as shown in Fig. 8, namely, the pilot lamps 3l and 32. The terminal 38 presents a central take-off or tap 33 whereby these pilot lamps may function properly, and at the same time provide a desired amount of current to the Various radio tubes or the radio receiving set.

Under some circumstances the resistance unit shown in Figs. l and 2 may be used in the circuit illustrated in Fig. 8, wherein the resistance members 23 and I6 are connected in a slightly different'manner as far as the circuit of the radio is concerned, but are juxtapositioned so that the resistance I6 will receive heat from resistance 23, and also so that pilot lamps 3l and 32 will be properly protected. It will be noted that the unit shown in Fig. l is adapted to accomplish desirable results as illustrated in Figs; 7 and 8, and to produce a necessary amount of resistance when maximum heat is generated in the voltage dropping resistors. It will also be noted that the entire assemblage, except the end of the terminals, is embedded in the asbestos insulation and tightly enclosed in the metal casing. The heat generated inside rthis casing is practically instantaneous, which makes the teinperature coefcient resistance I6 respond simultaneously and the device to become operative within a Very few seconds from the time current is turned on. This conditon results in eilcient loperation and a safeguarding of the pilot lamp to cause it to produce maximum Villumination at the time the 'radio receiving set begins to function.

In Figs. 9 to 13, inclusive, a slightly modified construction is shown which is utilized when the circuit shown in Fig. 14 is used. As shown in these iigures, there is provided an insulating strip 35 which may be mica, asbestos, or some other desired insulating material, and on top of this.

stripis positioned a resistance unit 36 which is a temperature coecient resistance unit similar to Fig. 3, except for the arrangement of the terminals 3l, 38 and 39. These terminals are each provided with turned over edges on one end to form laterally extending anges which act as bases for the terminals. The base of terminal 38 fits fiatwise against resistance 36 on one side, while the bases of terminals 3l and 39 t atwise against the opposite face, though they could all fit against the same face Withoutdeparting from the spirit of the invention. In this form of invention the casing I is provided with a suitable number of apertures for receiving all of the terminals. It will be evident, however, that instead of having a number of apertures there could be provided a continuous opening from substantially .one end of the device to the other, so that the terminals. could project therethrough Without'contacting therewith.y

As iuustrated in Figs. 5 and 13 the easing l is provided with an opening 40 extending for the full length'of the device and, if desired, the cassulation 35 are arranged spacing blocks 4l and 42 which may be of any suitable insulation as, for instance, asbestos, and on top of these blocks is a strip 43 of insulation which may be mica, asbestos, or some other insulating material. The strip 43 contacts with the blocks just mentioned and also presses against the resistance 36 and the bases of terminals 31 andv39. The end terminals 5 and 'l in this form of the invention have their bases overlapping the Vinsulating* strip 43 and pressing against these terminals is the standard resistance 23. It will 'be understood that the standard resistance 23 and also the resistance I6 consist of suitable wire wound on a suitable insulatirlg member which will resist heat as, for

instance, mica or asbestos. It will also be noted froman examination of Fig. 2 that the standard resistance 23 is in electrical engagement with the terminals 5 and 'l but is not any where in contact with vthe resistance 36, but the heat from the standard resistance quickly heats up re sistance 36 and causes the same to function in the desired manner. The resistance unit may havedevices connectedtothe terminals 5 and 1 without in any way being connected to the resistance 36, and in turn theresistance 36 could be connected to one or two members without being in the circuit ci' the element 23. However, in certain types of radio sets the wiring is arranged as shown in Fig. 14. From this it will be observed that two lamps 34 are tapped o i from the various terminals 31, 38 and 39, and that the tubes 21' are arranged in a slightly different manner from that shown in Fig. 7, the same receiving current which has passed through resistance 23. While the arrangement shown'in Fig. 14 is desirable in many circumstancesit will be evident that the resistance unit shown in Fig. 12 could be connected to other circuits without departing from the spirit `of the invention and the heating of the t'empera- 4ture coefficient resistance 36 would take place as above' described. It will, therefore, be seen .thatif desired it is not necessary for the current passing through the resistance to also pass through resistance 36, but as shown in Fig. 12, the resistance 23 may act, as far as resistance 36 is concerned, merely as a heater.

As the complete resistance units illustrated in Figs. 1 and 9 are simple and strong in construction, they readily lend themselves to adoptionin the manufacture of radio receiving sets and other devices; the cost .of production is comparatively low, and in most instances not more than a single voltage dropping resistor ordinarily employed in transformerless receivers now in use.

I claim:

1. A resistance unit including a secondary resistance, a primary terminal arranged at one end of said secondary resistance, an auxiliary terminal connected with said secondary resistance at the' other end, a third terminal spaced from said secondary resistance, a strip of insulating material extending from a point in front of said third terminal past said auxiliary terminal in back thereof and to a point near said primary terminal, a primary resistance of a length to have one end portion tted -against said primary terminal and the opposite end portion against said third terminal, an insulating member surrounding both of said resistances, and a metal casing substantially surrounding said insulating member for clamping all the parts together whereby there will be a good electrical contact between the respective terminals and the resistances, and the primary resistance held so that heat generated thereby will heat the secondary resistance.

2. A resistance unit, comprising a iiat primary resistance element appreciably longer than it is wide, a sheet of insulating material of substantially the same width as said primary resistance unit arranged on top of said element and extending from one end to near the other end, a flat secondary resistance element of substantially the same width as said primary resistance element but of less length, arranged on top of said sheet of insulating material so thaty one end thereof will extend over said other end of said primary resistance element. a pair of terminals permanently secured to said flat secondary resistance element at the end's thereof, said terminals having portions extending beneath said flat secondary resistance element with one of said portions contacting with said other end of said primary resistance element,A y a single terminal for said primary resistance element positioned at the end thereof opposite said other end, said last-mentioned terminal having a base extending beneath said sheet of insulating material and into contact with said primary resistance element, an insulating enclosure for both of said resistance elements and the bases of all of said terminals, and a metal casing enclosing said insulating enclosure, said metal casing acting to protect said resistance elements and also to prem the same toward each other whereby the primary resistance element will continuously and firmly engage one of the terminals on said flat secondary resistance element.

JOHN J. Mucrma. 

